US President Donald Trump launched a scathing attack on former top adviser Steve Bannon, responding to a new book that portrays Trump as an undisciplined man-child who didn't actually want to win the White House and quotes Bannon as calling his son's contact with a Russian lawyer "treasonous."

Hitting back via formal White House statement rather than a more typical Twitter volley, Trump insisted Bannon had little to do with his victorious campaign, AP wrote.

It was a blistering attack against the man who helped deliver the presidency to Trump, spurred by an unflattering new book by writer Michael Wolff that paints Trump as a leader who doesn't understand the weight of the presidency and spends his evenings eating cheeseburgers in bed, watching television and talking on the phone to old friends.

Harder sent Bannon a letter saying the former Trump aide violated confidentiality agreements by speaking with Wolff. The letter demanded Bannon "cease and desist" any further disclosure of confidential information.

White House aides were blindsided when early excerpts from "Fire and Fury: Inside the Trump White House" were published online by New York magazine and other media outlets ahead of the Jan. 9 publication date.

The release left Trump "furious" and "disgusted," said White House Press Secretary Sarah Huckabee Sanders.

New York magazine published a lengthy adaptation of the book on Wednesday, in which Wolff writes that Trump believed his presidential nomination would boost his brand and deliver "untold opportunities" — but that he never expected to win.

It says Trump Jr. told a friend that his father looked as if he'd seen a ghost when it became clear he might win. The younger Trump described Melania Trump as "in tears — and not of joy."

Wolff said in an author's note that the book was based on more than 200 interviews, including multiple conversations with the president and senior staff.